Carburizing box



Dec; 31, 1935. H. H. HARRIS CARBURIZING BOX Filed Aug. 9, 1934 2Sheets-Sheet l INVENTOR HENRY H. HARRIS ATTORNEYS Dec. 31, 1 9,35-HIHARR|S I 2,026,311

. CARBURIZING BOX Filed Aug. 9, 1934 2 Sheets-Sheet 2 INVENTOR HENRY H.HARRIS #Mmq ' ATTORNEYS a, an advance over the art. Y

so constructed in I Patented Decmem s,

j flnenre n. amen,

l Application a,1as4 ,serie1m.s3s,13sf

This invention reietee to We and t is an improvementon the invention"ofnrv -Patent No. 1,882,580.

It is an object of my'inventiontdprovide a carburizing box :wmcn willstandup. better and longerunderthe severe usage which such boxesreceive. y his a further object'ofmylinventiontoprm;

1 vide a carburizing. box whichwill havea longer 1o servioelife inproportion to the :dimcultyand exf pense of making same. I; 1 Otherobjects will appear in, the course .ofthis about the edges of the centerpart B, with forks;

specification. so i H V i ,l when carburizingeboxes are tobe used inheat a v 15 treating furnaces, nietalgarticlespto bewcarburized are.plac'edin'F the boxes, together with a car I burizing agent ,such ,as,bone ;.du st.;;j#Irays are placedover theboxes, the boxes with theirtrays i are then usually inverted, andin this position,

so are subjected in a heattreatingfurnace to heat i usually suppliedfrombeneath. i e The boxes must stand up under rough han- H dling,extremely high temperatures, 7 sudden 1 changes in temperature, and "thepressure of a aa heavy load of contents I 1 s arping and buckling,prowhile softened by heat, all with attendantw du'cing cracks andultimately breaking th'ebox down.

As a result, if the boxes were not madeso so to have great durabilityunder such treatment they would have to be replaced constantly att ggreat expense, and it becomes'a problem of some.

nicety and importance todevise a box having the longest life inproportion to the cost of pro-f 8t du'cing same, in which my inventionwhich is ilherewith represents lustrated in the drawings In saiddrawings, 1,- Fig. 1 is a pegspective view of one form of-boxccordancewith my invention; Fig. 2 is a longitudinalsectionalviewthereof 2I'of Fig. 1; and N e Fig. 3 is a broken transversesectionalfyiew onlinet-Iofligl, 45 gml 'lg. 4 is a plan view of a secondform pf box f constructed in accordance with my inventions;

Fig. 5 is a side view thereof:

Fig. 6 is a longitudinal sectional view. thereof line He: Fig. 4;

Fig. 7 is'a transverse sectional'qview thereof on"? line 1-1 of Fig. 5;and

' 1 l 1, Fig. an a transverse sectional view mm: on

linel-l of m. 5;

I im the am formgshown in mg; 1-3, the box is' ,made up of three parts,-A.VB and 0. Theend parts-A and C providepartial'bottom andside walls andalso end walls. The centeri part is U- shaped and open-ended, providingpartial bottom andsidewallsx t -'I'he center part B isfonned.aiplurality of reverse curve corrugations extending.continuouslydownoneside, across the bottom and up i the other side,producing substantially aebellows which is free 't yield"principallydengthwise of the box. h 7 The-end parts Aand 0- preferablyterminate in marginal portions facing each: other and cast ll and-l2embeddingsame. it To securea locked joint, holes 13 are formed along;the edges of 15 B and ties I I; integral with the endparts are formedthrough these holes inthe casting :proe

securely lockingthe parts together.

1 Strips Ii are welded to the centerpart Belong 'its upper edge, forminga reinforcement. at. the

tent. They could, however, be'stamped of sheet metal, instead of cast,and the joints could be made in other way such as welding orriveting.

The center part B is preferably formed from a sheet of high gradeductileheat resistant alloy,

such as a high nickel chromium alloy that islow in iron content, and thestrips ii are of the same material. i

In use the irregular expansion and contraction of the box has itsgreatest and most varied eflect longitudinally midway of the box. Suchstrains and variations are absorbed by the bellows part in thisconstruction, same being relatively free, especially when made of sheetmetal,

t expand, contract and twist in diflerent dlrec- 'tions moi'e freelythan any previous construction. The longitudinally wavy corner bends ofthis construction peculiarly adapt it to expansion,

contraction and twisting. While a single corrugation formed in thecenter part has essentially 'a reinforcing effect, the reversecurvesallow relatively free flexing to absorbs'trains which other-- wisewouldjultimately break the box down. The

solid anchoring of the more iiexiblejcenter m -in the more rigidendparts insures that the strains willbe transmitted to the part whichcan harmlessly absorb them, instead of their breakingloosethejoints l Inthesecond form, shown in Figs. 4-8, the box is made up of three parts E,F and G.

The end parts E and G provide partial bottom and side walls and also endwalls. The center part F is U-shaped and open-ended, providing partialbottom and side walls. The two end parts are joined to the center part,to. form a unitary box closed at-al1 sides but one.

The center part F is longitudinally corrugated all the way around, thecorrugations running from joined edge to. ioined edge thereof, provid-;ing substantially'a bellows with freedom'to yield in most directions andprincipally across the bottom and up and down the sidewall portions,convex'corrugations 2|, 22 of larger radius being formed where thebottom wall bends up into the side walls. a

The end parts E and G have generally flat walls except part F. Nearthese edges the walls of the end parts start gradually to assume acorrugated form indicated by reference character 23, which at the edgesmatches the corrugated form of the center At the edges the end partsareformed with two 7 forks 24, 25, which lie on both sides of the-part F tosecure the parts together. Positive locking between the parts ispreferably secured by forming, holes 26 along the edges of the centerpart and casting the end parts directly about the cen-. ter part withthe result that in the casting process ties 21 integral with theendpartsare formed through the holes, securely locking the parts together.'

:The. center: part F is preferably formed from a sheet ofa high gradeductile'heat resistant alloy, such as a high nickel chromium alloy, withlow iron content, while the end parts are preferably cast of a ruggedrelatively inexpensive metal or alloy, which may have a higher ironcontent.

In use the end portions provide the ruggedness to resist handling andrough usage; keep the expense down because made of cheaper material;

at the edges where they meet the center and are of a simple strongconstruction; but they cannot stand up so well under the strains ofwarping and buckling from temperature strains. The more ductile andflexible center part is provided to largely absorb these strains. Thecor- 5 rugated form of the center part gives it more adaptability tobend and twist. As an example, if one end part should expand along itsinner edge more than the other end part, this can all be taken up by afan-like spreading of the cor- 10 rugated center part. The corrugatingof the edges of the end parts makes a more pliable joint so'that bothparts can accommodate themselves to each other. The solid anchoring ofthe more flexible part in the more rigid parts insures that 15 thestrains will be taken up by those sections which can harmlessly absorbthem, instead of their breaking loose the joints. While I have shown twospecific forms to illustrate my invention, it will be apparent thatvari- 20 ations thereof may be made within the spirit of the invention,and hence I wish to be limited only by thescope of the appended claims.

I claim: 1. A metallic receptacle for use in heat treating 5 furnacescomprising two end parts each being a single integral castmember of arelatively high iron content, alloy and each providing an end wall and apartial bottom wall and partial side walls, and a center part formedofflexible sheet metal 30 of a relatively low iron content alloy andproviding a partial bottom wall and partial side walls and being formedthroughout its area with a plurality of continuous reverse corrugations,the inner edges being cast aboutthe edges of the center .35 part andanchored thereinto.

2. Device of claim 1 in which the corrugations are longitudinal and theend parts, at their edges adjacent the center part, gradually changefrom flat surfaces to corrugated form corresponding 40 with thecorrugations of the center part. I

HENRY H. HARRIS.

